Electric-arc lamp



(No Model.) I 2 Sl1eets-Sheet 1/ W. D'. RAY.

ELECTRIC ARC LAMP.

No. 557,229. Patented Mar. 31, 1896.

M M am,

(No Model.) 2 SheetsSheet 2.

w. D. RAY. ELECTRIC ARC LAMP.

No. 557,229. Patented Mar. 31, 1896. A. 1 651/975 UNITED STATES PATENT OFFICE.

IVILIJIAM D. RAY, OF CHICAGO, ILLINOIS.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 557,229, dated March 31, 1896.

Application filed July 11, 1894. Serial No. 517,260. (No model.)

To (LZZ whom it may concern.-

Be it known that I, WILLIAM D. RAY, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Electric-Arc Lamps, (Case No. 1,) of which the followingis afull, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electric-arc lamps, and its object is the provision of a compact lamp structure that shall combine simplicity of construction and efficiency of operation.

My invention consists, first, in an improved feeding mechanism; second, in an improved form of curved carbon-lamp; third, in certain details of constructions and organizations of parts adapted to insure effective operation, and, fourth, in such other features as will be hereinafter more particularly set forth.

I will describe my invention in connection with the accompanying drawings, in which Figure 1 is a side elevation ofacurved carbon-lamp embodying my invention. Fig. 2 is a partial sectional view of the same on. line 2 2 of Fig. 1. Fig. 3 is a plan view of the feeding mechanism. Fig. 4 is a detail view of a solenoid-core employed in one embodiment of my invention. Fig. 5is a detail view of a compensating device for changing the force exerted by the weight of the carbons. Fig. 6 is a modified form of feeding device embodying my invention. Fig. 7 is a sectional view, on a decreased scale, of a curved carbon-lamp casting, illustrating the enamel provided upon the surface to constitute a reflector. Fig. Sis a diagrammatic view of a lamp provided with a series coil equipped after the manner of my invention. Fig. 9 is a similar view of a lamp provided with a shuntcoil. Fig. 10 is a similar view of a lamp provided with differential coils. Fig. 11 is a similar view of a lamp provided with a core of uniform cross-section. Fig. 12 shows a lamp provided with a uniform core and a variably-wound solenoid.

Like letters refer to like parts in the several figures.

I will first described my invention in conuection with a curved carbon-lamp illustrated in Figs. 1, 2, and 3.

The frame comprises a plate a provided at the center with a downwardly-extending heinispherical portion a. An arch-piece b is secured to the plate, to which may be attached a hook or other device for suspending the lamp. Extending between bearings 11 19 provided upon the frame is a shaft 0, mounted upon which is an arm 0, supportinga core d, of continuously-decreasing cross-section from end to end. The core cl is adapted to move within a solenoid e, which, in the present instance, is connected in series with the carbons, the lamp being adapted for constant potential circuits, and more particularly designed for alternating currents, though the lamp may be used in connection with continuous currents.

Upon the shaft 0 is keyed a plate or sector 0 provided with a toothed circular periphery and carrying an arm 0 upon the end of which is provided the carbon-clamp 0 The toothed plate 0 meshes with a pinion 0 carried upon a shaft 0 a second pinion 0 being provided upon the same shaft and adapted to mesh with apinionf, mounted upon the shaft f a second pinion f being provided upon said shaft and adapted to mesh with the toothed periphery of a plate or sector f mounted upon a shaft f rotating in bearings f f. The sector f carries an arm f upon the end of which is provided the carbon-clamp f As the shaft 0 rotates, due to the action of the solenoid or electromagnet e, the plates 0 and f are rotated in opposite directions through the agency of the intermediate gearing, and the carbons thus caused to approach or recede. In the form of lamp illustrated two slots 9 g are provided in the frame of the lamp, through which slots the arms c and f supportin the carbons, may travel.

here desired,the slots may be omitted and the arms 0 and f I so arranged that their movement takes place entirely above the plate a, in which case it will be necessary only to provide holes in the plate a, through which the carbon rods may extend.

Upon the under surface of the hemispherical portion a of the frame and upon the under surface of plate a, when desired, is placed a reflecting enamel or other reflecting surface, which serves to reflect the light projected from the arc. In Fig. 7 is illustrated an enamel 7L, indicated in black, placed upon the surface of the portions to and a.

The operation of the lamp, as above described, is as follows: The lamp being cut from the circuit, the carbons rest in contact, so that when current is turned on the current traverses the carbons and the solenoid e, which, in the present instance, is connected in series therewith. The solenoid 6 being thus energized, the core (1 is attracted and drawn into the solenoid, the core moving in such a direction that the portion of the core within the solenoid is increased in mass. The carbons are thus separated and an arc established. As the arc consumes the carbons the arc increases in resistance, and, the lamp be ing employed upon a constant potential circuit, the current decreases. The solenoid 6 thus exerts a decreased pull upon the core d, and the weight of the carbons serves to withdraw the core (Z from the solenoid, thus moving the carbons toward one another and decreasing the resistance of the arc to bring the current back to its normal value. The core remains in its new position until the current again falls below the normal, when, the weight of the carbons overcoming the pull of the solenoid, the carbons are again moved toward one another to bring the current back to its normal value and to maintain the carbons at the proper distance apart. If the current is increased above the normal, the core is moved in an opposite direction to separate the carbons. The lamp is thus self-regulating.

hen alternating currents are employed, the core cl need not be of magnetic material, though I prefer to construct the core of laminated iron. Vhen non-magnetic material is employed, the eddy or Foucault currents induced in the core by the varying magnetic field of the solenoid react to produce the desired movements of the core.

Instead of employing the tapering core as the core of an electromagnet in the form of a solenoid, I may employ it for the purpose of varying the reluctance of a magnetic circuit to thereby secure the required movement of the core. As illustrated in Fig. 6, the electromagnet 6 takes the form of a piece 8 of magnetic material, the ends 6 6 being provided with openings through which the core (Z may pass. The core (Z is mounted to rotate about an axis, as in the former case. So long as the current is normal the core remains stationary. Upon a decrease of the current the weight of the carbons overcomes the pull of the magnet and the core moves in cl0ckwise direction until the current is brought back to the normal, and then the core comes to rest, the feed of the carbons being thus effected.

As the carbons move during the feeding of the lamp, the weight of the carbons, and the lever-arm through which their weight acts,

is constantly changing. In order to compensate for this change, I have provided a friction-roller. (Illustrated in Fig. Mounted to rotate with the arm supporting the carbon is an arm '2', upon the end of which is a longitudinally-movable sleeve 1" carrying a roller 2' which bears against a cam-guide i A spring 1' tends to press the roller outward. The surface of the guide 2' is properly proportioned, so that as the moment of the force due to the weight of the carbon rods is increased the roller is moved inward to increase the pressure with which the roller bears against the guide, to thereby increase the friction of the roller upon the guide and thus produce a retarding effect to compensate for the increased rotating effect of the carbons. As the moment due to the weight of the carbons decreases, the retarding effect is correspondingly decreased by the outward movement of the roller.

It will be observed that the feeding mechanism thus provided effects a positive movement of the carbons, the core during the operation of the lamp partaking of a continuous movement from one position to another, the intervention of friction-clamps, pawls and ratchet movements, and other impositive devices being thus avoided.

My improved feeding mechanism may when desired be employed with impositive devices, such as pawls and ratchets. Further, the feeding and compensating mechanism may be equally applied to straight carbon-lamps.

Fig. 8 illustrates diagrammatically my invention as employed with a series coil.

Fig. 9 illustrates the lamp employed in connection with a shunt-coil, in which case, during the progress of the burning of the carbons, the core is pulled into the coil to effect the feed.

Fig. 10 illustrates a lamp provided with a differential coil, the shunt-coil serving, as the resistance of the arc increases, to weaken the effect of the series coil to permit the withdrawal of the core to effect the feeding operation.

Fig. 11 is illustrative of a lamp provided with a core of uniform cross-section, with which core a compensating device, such as that illustrated in Fig. 5, may be employed to effect the feed in a similar manner to that secured when a tapering core is used. The pull exerted by the coil upon the core decreases as the end of the core is drawn into the coil until when the middle of the core occupies a position in the middle of the coil the pull is zero. Therefore, when this form of core is employed, the counterpull occasioned by the weight of the carbons must be decreased in the same proportion that the pull of the coil is decreased in order that the core may remain at equilibrium at all positions of the carbons. This decrease of the pull due to the carbons may be effected by the employment of some form of retarding device, such as that shown in Fig. 5, the guide being so proportioned that, as the carbons feed, the friction is varied to continuously decrease the counterpull due to the carbons. When the tapering core is used, this balance is secured by the taper of the core, the pull exerted by the coil upon the core being the same at the several positions of the core within the limits of its travel, while the pull due to the movement of the carbons is kept constant. In the former case the pull of the coil varies and the counterpull due to the carbons is likewise varied to maintain equilibrium. In the latter case the pull due to the coil is maintained constant, as is also the counterpull due to the carbons.

In practice it may not be practicable or desirable to so proportion the tapering core that the pull of the coil thereon will be constant, and the balance may be secured by properly fashioning the guide-surface upon which the frictionroller travels to maintain the two forces continuously balanced.

Instead of tapering the core or varying the pull exerted by the carbons, the same effect may be produced by maintaining the pull exerted by the carbons constant and effecting the uniform pull exerted by the solenoid upon the core by winding the solenoid with a variable number of turns, the number increasing toward the ends, as shown in Fig. 12, whereby the pull upon the core at all points within its working travel will be constant. Furthermore, instead of mounting the core to move to feed the carbons, the solenoid or electromagnet may be so mounted and the core maintained stationary, which latter construction I consider the equivalent of the former.

lVhile I have described the feeding mech-' anism in connection with a curved carbonlamp, it may be applied with equal effect by the necessary structural changes to straight carbon-lamps.

hen the lamp is used in connection with alternating currents, the inductive eifect produced by the insertion of the core into the helix assists in maintaining the current constant. Thus when the arc decreases in length and the current tends to increase, the increase of current pulls the core into the solenoid, thus offering an added resistance to the passage of the current at the same time the carbons are moved apart to decrease the current.

It is evident that the several features of my invention are susceptible of modifications, and I do not therefore desire to limit myself to the precise constructions shown; but,

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an arc-lamp, the combination with a curved tapering core mounted to rotate about an axis, of an electromagnet threaded by said core, carbon-carriers supporting curved carbons and mounted to rotate about an axis, and a frictional device for increasing or decreasing the friction tending to retard the descent of the carbons to compensate for the variations of the pull exerted thereby, sub stantially as described.

2. In an arc-lamp, the combination with carboncarriers supporting curved carbons and mounted to rotate about an axis, of an arm mounted to rotate therewith, a spring-pressed longitudinally-movable sleeve mounted upon said arm, a roller carried upon said sleeve and a cam-guide adapted to be engaged by said roller, substantially as described.

3. In an arc-lamp, the combination with the core at mounted upon the shaft 0, of the sector a mounted to rotate therewith, the sector f and the gearing between said sectors, substantially as described.

4. In an arc-lamp, the combination with a curved core mounted to rotate about an axis, of an electromagnet for rotating said core, a pair of carbon-carriers mounted to rotate about pivotal axes, gearing between said carbon-carriers and said cores, and a device for variably reacting against the pull exerted by the carbon-carriers and the carbons, substantially as described.

5. In a curved carbon arc-lamp, the combination with the frame carrying the. downwardly-extending centrallysituated hemispherical portion, of the carriers for moving the curved carbons upon the exterior of said hemispherical portion, a curved core mounted to rotate within said hemispherical portion, and an. electromagnet for moving said core and connecting means between said core and said carbon carriers; whereby a compact structure of minimum height results and the hemispherical portion may serve to diffuse the light; substantially as described.

6. In an arc-lamp, the combination with the casting or frame having a horizontal por tion and a centrally-located hollow hemispherical portion extending below the horizontal portion, of the electromagnet supported upon a frame resting by the ends upon the opposite sides of said hollow hemispherical portion, a rotatably-mounted curved core moved by said electromagnet and situated partially within said hollow hemispherical portion, a pair of carbon-carriers mounted to maintain the carbons in position upon the outside of said hemisherical portion and to feed the same together, and gearing between said core and said carbon-holders; substantially as described.

In witness whereof I hereunto subscribe my name this 29th day of June, A. D. 1894:.

IVILLIAM D. RAY.

\Vitnesses W. CLYDE J ONES, GEORGE L. CRAGG. 

